A By-product is a material, other than the principal product, generated as a consequence of an industrial process or as a breakdown product in a living system.
There are basically two types of by-product materials. The first are produced by a nuclear reactor and the second are produced by the uranium and thorium mining process. A more precise definition reads: "(1) Any radioactive material (except special nuclear material) yielded in, or made radioactive by, exposure incident to the process of producing or utilizing special nuclear material, and (2) The tailings or wastes produced by the extraction or concentration of uranium or thorium from ore processed primarily for its source material content, including discrete surface wastes resulting from uranium solution extraction processes. Underground ore bodies depleted by these solution extraction operations do not constitute "by-product material" within this definition (10 CFR 20.1003)."
"By-product" is in the NAICS Code "311612"
Meat Processed from Carcasses
... bones, and meat scraps-are classified in U.S. Industry 311613, Rendering and Meat By-product Processin ...
List of books: By-product